Customer Asking for a W-9: How to Fill It Out and Verify the Request

When a customer asks you to fill out a W-9, they’re treating you as an independent contractor and need your taxpayer identification information so they can report what they pay you to the IRS. The form itself, Form W-9 (“Request for Taxpayer Identification Number and Certification”), collects your legal name, business type, and taxpayer identification number (TIN). Your customer keeps it on file and uses it to prepare a year-end Form 1099 showing what they paid you.¹

Fill it out, sign it, and send it back through a secure channel. The rest of this article walks through why the request exists, how to complete each line without creating problems for yourself, and what goes wrong if you don’t respond.

Why the Request Exists

Federal law requires businesses to track payments to independent contractors, freelancers, and other non-employees, and to file an information return with the IRS once those payments cross a reporting threshold in a calendar year. That return is usually a Form 1099-NEC for non-employee compensation, or occasionally a Form 1099-MISC for rent and certain other payments. The W-9 is simply how your customer collects the data they need to prepare that filing.²

The threshold is changing. For years it sat at $600. Starting with tax year 2026, businesses must file a 1099 once payments to a non-employee reach $2,000 or more in a year, with inflation adjustments beginning in 2027.² A customer who doesn’t yet know whether they’ll cross that line will often ask for the W-9 up front just in case.

Reporting is generally required for payments to individuals, sole proprietors, partnerships, and certain LLCs. Payments to C corporations and S corporations are usually exempt, which is one reason the form asks for your business type: your customer uses that answer to decide whether they even need to file a 1099 for you.²

What a W-9 Says About Your Work Status

Handing you a W-9 instead of a W-4 is itself a statement about the relationship. Employees fill out a W-4 (“Employee’s Withholding Certificate”) so their employer knows how much income tax to withhold from each paycheck.¹ A W-9 means you are being paid as a contractor: nothing is withheld, and you are responsible for setting money aside for both income tax and self-employment tax on your own.

If the way you actually work for this customer looks more like employment, controlled hours, assigned equipment, ongoing supervision, you can ask the IRS to decide. Form SS-8 is the request for a formal determination of worker status.³ It’s worth doing before the year’s income reports go out, not after.

Filling Out the Form

The W-9 is one page, and most mistakes happen on the classification lines rather than anywhere technical.

Lines 1 and 2: Name

Line 1 is your legal name. For a sole proprietor, that name must match the name on your Social Security card. A trade name or “doing business as” goes on Line 2. Corporations and partnerships put the registered legal entity name on Line 1.⁴

Single-member LLCs are where the most confusion happens. If you own a single-member LLC and haven’t elected to be taxed as a corporation, the IRS treats it as a “disregarded entity.” Your personal name goes on Line 1, the LLC name on Line 2, and your Social Security Number is the TIN, even if the LLC has its own EIN for payroll or banking.⁵

Line 3: Federal Tax Classification

Check one box describing how you’re taxed:

Individual or sole proprietor, which covers most freelancers, self-employed workers, and single-member LLCs taxed as sole proprietors.
C corporation or S corporation, for incorporated businesses.
Partnership, for multi-member partnerships.
LLC, with an added letter indicating how the LLC is taxed (C corporation, S corporation, or partnership). A single-member LLC that hasn’t elected corporate treatment should not check this box; it files under the individual/sole proprietor rules instead.⁴

Line 4: Exemptions

Two optional fields. The exempt payee code applies mainly to corporations, government entities, tax-exempt organizations, and financial institutions, so most individual contractors leave it blank. The FATCA reporting exemption only matters if the account receiving your payments is held at a foreign financial institution. Domestic account, blank field.⁵

Part I: Your TIN

Which number you give depends on how you’re organized:

Individuals and sole proprietors use their Social Security Number.
Corporations, partnerships, and multi-member LLCs use the entity’s Employer Identification Number.
Non-citizens who have a federal tax obligation but aren’t eligible for an SSN use an Individual Taxpayer Identification Number (ITIN).⁶

Getting this right matters. Your customer sends the TIN to the IRS, which matches it against the name on file. A mismatch can trigger backup withholding on your next payments and penalties for the payer.⁴

Part II: Signature

You’re certifying under penalty of perjury that the name, TIN, and classification are correct and that you are not subject to backup withholding (or that you are, if the IRS has told you so). Sign and date it. An unsigned W-9 is incomplete and your customer will send it back.

Verify the Request Before You Send Your SSN

Before you put a Social Security Number on a form and email it to anyone, confirm the request is real. A customer who already has a contract with you or has paid you for work has an obvious reason to ask. A cold email from a sender you don’t know is a different situation.

The IRS specifically warns businesses about phishing requests and recommends verifying any emailed request by calling the sender directly.⁷ The same advice protects you. If a W-9 request shows up in your inbox from a new client, call a phone number you independently confirm (not one in the email) and verify they sent it before you reply with your SSN attached.

When you do send the form, use a secure channel. A vendor portal is best. Encrypted or password-protected email is the minimum. Plain unencrypted email with the W-9 as an attachment is the method to avoid; physical mail is safer than that.⁷

One way sole proprietors can reduce how often their SSN leaves their hands: apply for a free EIN online from the IRS and use that number on W-9s instead. It takes a few minutes and keeps your Social Security Number out of circulation.

What Happens If You Don’t Return It

Ignoring the request doesn’t stop the payments; it changes them. When a payer can’t get a valid TIN, they are required to withhold 24% of every payment and send it to the IRS. This is backup withholding, and it also applies if the TIN you provide doesn’t match IRS records or if the IRS has notified you about underreporting income.⁸ The 24% comes off the gross payment, before any of your expenses.⁹

The money isn’t lost. It credits your tax account and you can claim it when you file. But collecting 76 cents on the dollar in the meantime can wreck a small operation’s cash flow. To stop backup withholding, fix whatever caused it, usually by providing a corrected W-9 with the right TIN and certification.⁸

Penalties for False Information

Because you sign under penalty of perjury, the W-9 carries real consequences for inaccurate answers:

Failing to provide your TIN brings a $50 penalty per failure, unless you can show reasonable cause.⁵
Falsely claiming exemption from backup withholding without a reasonable basis carries a $500 civil penalty.
Willfully falsifying the form can result in criminal fines and imprisonment.⁵

The IRS generally distinguishes a typo from fraud, but double-check your TIN and classification before signing anyway.

When to Send a New W-9

A W-9 doesn’t expire, but some changes require you to send an updated form to every customer who has one on file:⁵

Your legal name changes through marriage, court order, or business restructuring.
Your TIN changes, such as switching from an SSN to an EIN.
Your tax classification changes, for example, a C corporation electing S corporation status, or an entity losing tax-exempt status.
You claimed exempt payee status previously and no longer qualify.

Some customers also ask for a fresh W-9 every year or two as internal policy. That isn’t an IRS requirement, but it’s easier to comply than to argue.

What Comes After: The 1099

After you submit the form, it sits in your customer’s files until year end. They then issue a Form 1099-NEC reporting what they paid you. Your copy should arrive by January 31 of the following year, and a matching copy goes to the IRS linked to your TIN.¹⁰

The 1099 reports gross payments, not profit. Deductions for materials, software, subcontractors, and other business expenses come later, on your own return. The important thing while you still have time to fix problems: compare the 1099 against your own records. Any gap between what the IRS received and what you report will generate an automated notice.

If the number is wrong, contact your customer first and ask for a corrected 1099. Most will issue one once you point out the error. If you can’t get a corrected form by the end of February, call the IRS at 800-829-1040 with your information, the payer’s details, and the disputed amounts ready.¹¹

One last point about the new $2,000 threshold: no 1099 does not mean no tax obligation. You owe income tax and self-employment tax on everything you earn, whether or not a 1099 is issued. The 1099 is a reporting tool for the payer; your duty to report income exists independently.²

1
Internal Revenue Service. About Form W-9, Request for Taxpayer Identification Number and Certification
2
Internal Revenue Service. 2026 Publication 1099 (Draft)
3
Internal Revenue Service. 1099-NEC and 1099-MISC Income Treatment Scenarios
4
Internal Revenue Service. Instructions for the Requester of Form W-9
5
Internal Revenue Service. Form W-9, Request for Taxpayer Identification Number and Certification
6
Internal Revenue Service. Individual Taxpayer Identification Number (ITIN)
7
Internal Revenue Service. Identity Theft Information for Businesses
8
Internal Revenue Service. Topic No. 307, Backup Withholding
9
Internal Revenue Service. Fast Facts to Help Taxpayers Understand Backup Withholding
10
Internal Revenue Service. Instructions for Forms 1099-MISC and 1099-NEC
11
Internal Revenue Service. What to Do When a W-2 or Form 1099 Is Missing or Incorrect